Cathode plate, battery cell and battery
By employing a three-layer composite structure and protrusion design in the lithium-ion battery cathode sheet, the problem of bare cells tearing during drops or tumbling is solved, enhancing tear resistance and cell flatness, and reducing safety risks.
Patent Information
- Application Number
- CN202520263915.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2035-02-19
AI Technical Summary
Existing lithium-ion batteries are prone to tearing of the bare aluminum foil or single-sided area of the cell under abuse conditions such as drops or tumbling, leading to safety issues. In addition, the poor flatness of the cell increases the risk of formation defects.
The cathode sheet adopts a three-layer composite structure, including a substrate layer and an active material layer. The substrate layer consists of an intermediate layer, an outer layer, and an inner layer. The intermediate layer is sandwiched between the outer and inner layers. The protruding structure is set on the intermediate layer. The active material layer is connected to the outer or inner layer. The protruding structure is wrapped by the surface layer, which enhances the structural stability and stress distribution uniformity.
It improves the tear resistance of the cathode sheet, reduces the risk of internal short circuits during drops or collisions, improves the flatness of the cell, and reduces the occurrence of formation defects.
Smart Images
Figure CN223693143U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to battery technology field especially relates to a cathode sheet, electric core and battery. BACKGROUND
[0002] Lithium ion battery has the characteristics such as high energy density, good cycle performance, is widely used in 3C digital products. People use mobile phones and other electronic products to fall phenomenon is common, according to the research data shows that more than about 80% of electronic product damage is because of falling or collision directly or indirectly lead to damage.
[0003] To improve the battery drop / roller and other failure performance, usually adopt double -sided tape or hot melt adhesive and other strengthen bare electric core and aluminum plastic film fixed mode, this mode can reduce the movement of bare electric core collision, but this measure is easy to cause the end empty aluminum foil or single -sided area tear, further cause safety problem. UTILITY MODEL CONTENT
[0004] The utility model discloses a kind of cathode sheet, electric core and battery, can enhance the anti-tearing ability of bare electric core cathode sheet whole and especially the end empty aluminum foil or single -sided area, reduce drop / roller and other abuse failure, while improve electric core flatness.
[0005] To achieve the above object, some embodiments of the utility model propose a kind of cathode sheet, including substrate layer and active material layer, substrate layer includes middle layer, outer surface layer, inner surface layer and protruding structure, middle layer is clamped between outer surface layer and inner surface layer, protruding structure is set on middle layer, active material layer is at least connected with the side of outer surface layer away from middle layer and / or inner surface layer away from middle layer;
[0006] Wherein, protruding structure connects the side of middle layer towards outer surface layer, and outer surface layer wraps protruding structure, and / or protruding structure connects the side of middle layer towards inner surface layer, and inner surface layer wraps protruding structure.
[0007] In some embodiments, protruding structure includes first protrusion and third protrusion, active material layer includes long film surface active material layer and short film surface active material layer, long film surface active material layer connects inner surface layer, short film surface active material layer connects outer surface layer, along the length direction of cathode sheet, the length of long film surface active material layer is longer than the length of short film surface active material layer, and along the length direction of cathode sheet, the end of first protrusion and the end of short film surface active material layer are flush, the end of third protrusion and the end of long film surface active material layer are flush.
[0008] In some embodiments, the short-film active material layer and the first protrusions are distributed along the length direction of the cathode sheet, the long-film active material layer and the third protrusions are distributed along the length direction of the cathode sheet, the first protrusions and the short-film active material layer are flush along the thickness direction of the cathode sheet, and the third protrusions and the long-film active material layer are flush along the thickness direction of the cathode sheet.
[0009] In some embodiments, the height H1 of the first protrusions and the third protrusions each satisfies 0 μm < H1 ≤ 100 μm, the length L1 satisfies 10 mm ≤ L1 ≤ 400 mm, and the width D1 satisfies 10 mm ≤ D1 ≤ 200 mm.
[0010] In some embodiments, the first protrusions extend along the length direction of the cathode sheet, and along the length direction of the cathode sheet, the end of the first protrusions and the end of the long-film active material layer are flush; and / or,
[0011] The protrusion structure includes a plurality of first protrusions distributed along the length direction of the cathode sheet, and along the length direction of the cathode sheet, the end of the first protrusion located at the end of the cathode sheet and the end of the short-film active material layer are flush, and the recess between the plurality of first protrusions is suitable for connecting the hot melt adhesive.
[0012] In some embodiments, the first protrusions extend along the length direction of the cathode sheet, and along the length direction of the cathode sheet, the end of the first protrusions and the end of the short-film active material layer are flush; and / or, the protrusion structure includes a plurality of second protrusions distributed along the length direction of the cathode sheet, and along the thickness direction, the plurality of second protrusions are connected to the side of the first protrusion away from the intermediate layer and are arranged above the first protrusion, the plurality of second protrusions and / or the recess between the second protrusions are suitable for connecting the hot melt adhesive, and / or along the length direction of the cathode sheet, the distance between the end of the second protrusion and the end of the first protrusion is between 20 mm and 100 mm.
[0013] In some embodiments, the height H2 of the first protrusion and / or the second protrusion and / or the third protrusion satisfies 0 μm < H2 ≤ 100 μm, the length L2 satisfies 10 mm ≤ L2 ≤ 400 mm, and the width D2 satisfies 10 mm ≤ D2 ≤ 200 mm.
[0014] The interval S of each first protrusion and / or second protrusion and / or third protrusion satisfies 0 ≤ S ≤ 90 mm.
[0015] In some embodiments, the intermediate layer includes copper foil and its alloy or other metal, alloy, the thickness H3 of the intermediate layer satisfies 1 μm ≤ H3 ≤ 6 μm, the length L3 satisfies 50 mm ≤ L3 ≤ 2450 mm, and the width D3 satisfies 10 mm ≤ D3 ≤ 200 mm.
[0016] The outer surface layer includes aluminum foil and its alloy or other metal, alloy, and the thickness H4 of the outer surface layer satisfies 0.5 μm ≤ H4 ≤ 3 μm.
[0017] The inner surface layer comprises aluminum foil and its alloys or other metals, alloys, and the thickness H5 of the inner surface layer satisfies 0.5 μm≤H4≤3 μm.
[0018] In some embodiments, the end of the long film active material layer and the third protrusion are connected and covered by the end tape along the thickness direction of the cathode sheet, the end of the short film active material layer and the first protrusion are connected and covered by the end tape, the end tape covers the end of the long film active material layer by 1mm-4mm and covers the third protrusion by 2mm-30mm along the length direction of the cathode sheet; and / or, the end tape covers the end of the short film active material layer by 1mm-4mm and covers the first protrusion by 2mm-30mm along the length direction of the cathode sheet.
[0019] The second aspect of the embodiments of the utility model provides a kind of battery, including the cathode sheet of any one of the above, and the battery further includes anode sheet and diaphragm, diaphragm is clamped between cathode sheet and anode sheet.
[0020] The third aspect of the embodiments of the utility model proposes a kind of battery, including the battery of any one of the above.
[0021] According to the above embodiment, the utility model has the beneficial effects that:
[0022] The cathode sheet of the utility model includes substrate layer and active material layer. The substrate layer is specifically structured to include intermediate layer, outer surface layer, inner surface layer and protrusion structure. The intermediate layer is clamped between the outer surface layer and the inner surface layer to form a three-layer composite structure. The active material layer is connected to at least one side of the outer surface layer away from the intermediate layer or one side of the inner surface layer away from the intermediate layer, to ensure that the active material can effectively participate in electrochemical reaction. The protrusion structure is arranged on the intermediate layer, towards the inner surface layer and / or the outer surface layer, and the surface layer wraps the protrusion structure. Because the protrusion structure is wrapped by the corresponding surface layer, the stability of the entire structure is ensured, and the delamination phenomenon that may exist in the traditional smooth interface is avoided.
[0023] Specifically, the metal or alloy skeleton of the base material layer enhances the tensile strength compared with conventional base materials, and the presence of the protrusions makes the stress distribution more uniform, reducing the possibility of tearing caused by external forces. When coating the active material, the protrusion structure can also help maintain the flatness of the end of the pole piece, avoiding the problem of uneven end of the cathode piece that may occur due to the different lengths of the active material layer coated inside and outside the cathode piece in the traditional method. Therefore, the application improves the anti-tearing ability of the cathode piece, especially the end area and the hot melt adhesive area, reduces the risk of internal short circuit when the battery falls or collides, and when applied to the battery cell, improves the flatness of the battery cell, thereby reducing the probability of formation failure. At the same time, the protrusion structure aligns the end of the cathode long film and / or the cathode short film in the length direction, and the protrusion structure aligns the active material layer of the cathode long film and / or the cathode short film in the thickness direction, improving the overall flatness of the battery cell caused by the film length difference of the cathode long film and short film.
[0024] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS
[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in the drawings without creative labor.
[0026] Figure 1 The structure schematic diagram of the cathode piece in the first embodiment of the present application is shown in the figure.
[0027] Figure 2 The structure schematic diagram of the cathode piece in the second embodiment of the present application is shown in the figure.
[0028] Figure 3 The structure schematic diagram of the cathode piece in the third embodiment of the present application is shown in the figure.
[0029] Figure 4 The structure schematic diagram of the cathode piece in the fourth embodiment of the present application is shown in the figure.
[0030] Figure 5 The structure schematic diagram of the battery cell in an embodiment of the present application is shown in the figure.
[0031] EXPLANATION OF DRAWINGS:
[0032] The intermediate layer 100;
[0033] The inner surface layer 200;
[0034] outer layer 300;
[0035] raised structure 400; first raised portion 410; second raised portion 420; third raised portion 430;
[0036] long film surface active material layer 500;
[0037] short film surface active material layer 600;
[0038] tail tape 700.
[0039] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with embodiments. DETAILED DESCRIPTION
[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0041] It should be noted that if the present application embodiments involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.
[0042] In addition, if the present application embodiments involve descriptions of "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features with "first" and "second" can explicitly or implicitly include at least one of the features. In addition, if "and / or", "and / or", or "and / or" appear throughout the text, the meaning includes three parallel schemes. For example, "A and / or B" includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.
[0043] Reference Figure 1In some embodiments, the cathode tab of the first aspect of the present application comprises a substrate layer and an active material layer. The substrate layer is specifically configured to comprise an intermediate layer 100, an outer surface layer 300, an inner surface layer 200, and a protrusion structure 400. The intermediate layer 100 is sandwiched between the outer surface layer 300 and the inner surface layer 200, forming a three-layer composite structure. The active material layer is connected to at least one side of the outer surface layer 300 away from the intermediate layer 100 or one side of the inner surface layer 200 away from the intermediate layer 100, ensuring that the active material can effectively participate in electrochemical reactions. The protrusion structure 400 is connected to the side of the intermediate layer 100 facing the outer surface layer 300 and / or the inner surface layer 200, and the outer surface layer 300 and / or the inner surface layer 200 completely wrap the protrusion structure 400. Because the protrusion structure 400 is wrapped by the corresponding surface layer, the stability of the entire structure is ensured, and the delamination phenomenon that may exist in the traditional smooth interface is avoided.
[0044] Specifically, the metal or alloy framework of the substrate layer of the present application enhances the tensile strength compared to conventional substrates, and the presence of protrusions makes the stress distribution more uniform, reducing the possibility of tearing caused by external forces. When coating the active material, the protrusion structure 400 can also help maintain the flatness of the end of the tab, avoiding the problem of uneven ends of the cathode tab that may occur due to the different lengths of the active material layer coated inside and outside the cathode tab in traditional methods. Therefore, the present application improves the tear resistance of the cathode tab, especially the end and hot melt glue area, reduces the risk of internal short circuit when the battery falls or collides, and improves the flatness of the battery when applied to the battery, thereby reducing the probability of formation failure. At the same time, the protrusion structure 400 is aligned with the end of the long and / or short cathode film in the length direction, and the protrusion structure 400 is aligned with the active material layer of the long and / or short cathode film in the thickness direction, improving the overall flatness of the battery due to the difference in film length of the long and short cathode films.
[0045] It should be noted that, regarding the inner surface layer 200 and the outer surface layer 300, the inner surface layer 200 is defined as the side of the cathode tab that is not coated with an active material layer facing inward when the substrate region of the cathode tab is used to form a battery, and the outer surface layer 300 is defined as the side of the cathode tab that is not coated with an active material layer facing outward when the substrate region of the cathode tab is used to form a battery.
[0046] It can be understood that, in some embodiments, the protrusion structure 400 can be regularly arranged cylindrical protrusions, square protrusions, conical protrusions, or irregularly shaped granular protrusions, etc. Different geometric shapes will affect the specific surface area and porosity of the electrode material, and in turn affect the lithium ion diffusion rate and electrical conductivity. For example, regular arrangement of cylindrical, square or conical shapes can provide uniformly distributed additional surface area while maintaining high mechanical strength, which is beneficial to improve the charge and discharge efficiency; irregularly shaped particles can create more randomly distributed small pores, enhance electrolyte wettability and promote ion exchange.
[0047] In some embodiments, the material selection of the protrusion structure 400 and its impact on the overall performance are considered. The protrusion structure 400 can be manufactured using the same material as the base material layer to ensure good bonding force between the two; or a metal or alloy with higher electrical conductivity can be selected as the protrusion material, such as copper, nickel, etc., so that lower resistance loss can be maintained even under high rate charging and discharging conditions. In addition, a functional coating can also be introduced to cover the protrusion surface, such as a carbon coating or other conductive polymers, which can not only improve the conductivity at the interface but also play a certain protective role to prevent corrosion problems after long-term use.
[0048] In some embodiments, for the wrapping relationship between the protrusion structure 400 and the surface layer, in addition to direct physical wrapping, the connection strength between the two can also be strengthened through chemical bonding. For example, a thin and dense oxide or nitride film is grown on the protrusion surface using atomic layer deposition (ALD) technology, and then the material of the outer surface layer 300 is deposited, so that firm bonding can be achieved at the molecular level, greatly reducing the possibility of interface defects, and ensuring long-term stability and safety in dynamic working environment.
[0049] Referring to Figure 1 , Figure 4 and Figure 5In some embodiments, the protruding structure 400 includes a first protrusion 410, the active material layer includes a long-film-face active material layer 500 and a short-film-face active material layer 600, the long-film-face active material layer 500 is connected to the inner surface layer 200, the short-film-face active material layer 600 is connected to the outer surface layer 300, the length of the long-film-face active material layer 500 is longer than the length of the short-film-face active material layer 600 along the length direction of the cathode sheet, and the end of the first protrusion 410 is flush with the end of the short-film-face active material layer 600 along the length direction of the cathode sheet. This layout ensures uniform coverage of the active material layer on the entire cathode sheet, especially good adhesion in the edge area. Specifically, along the length direction of the cathode sheet, the end of the long-film-face active material layer 500 is closer to the end of the cathode sheet, and the long-film-face active material layer 500 and the short-film-face active material layer 600 have different spacings at the end of the cathode sheet, which can easily lead to unevenness in the winding end area when winding the bare cell. The design of the flush end of the first protrusion 410 and the end of the short-film-face active material layer 600 provides sufficient support at both ends of the cathode sheet, avoiding local stress concentration caused by edge effects. When the battery is working, the current distribution is more uniform, reducing the risk of uneven corrosion of the electrode surface. In addition, the first protrusion 410 as a support point can also help to disperse the pressure from the outside and protect the internal sensitive components from damage. This design achieves uniform distribution of the active material layer over the entire length of the cathode sheet, especially strengthening the structural integrity of the end, improving the safety and reliability of the battery.
[0050] It can be understood that in some embodiments, the first protrusion 410 can be a small protrusion arranged at the end of the cathode sheet, or a long protrusion extending from the end of the short-film-face active material layer 600 to the end of the cathode sheet, as long as the thickness on one side of the short-film-face active material layer 600 at the end of the cathode sheet is compensated by the addition of the first protrusion 410.
[0051] Referring to Figure 4 and Figure 5In some embodiments, the short-film active material layer 600 and the first protrusion 410 are distributed along the length direction of the cathode sheet, and along the direction from the intermediate layer 100 to the outer surface layer 300, the height of the short-film and the height of the first protrusion 410 are consistent, and / or the long-film active material layer 500 and the third protrusion 430 are distributed along the length direction of the cathode sheet, and along the direction from the intermediate layer 100 to the inner surface layer 200, the height of the long-film and the height of the third protrusion 430 are consistent. When the height of the short-film active material layer 600 and the first protrusion 410 are the same and / or the height of the long-film active material layer 500 and the third protrusion 430 are the same, the active material layer can form a continuous and uniform interface in the entire length direction of the cathode sheet. This not only helps to improve the uniformity of the current distribution inside the battery, but also reduces the risk of material peeling or delamination due to local stress concentration. In addition, this height consistency also helps to achieve more accurate coating control during the manufacturing process, ensuring stable and reliable product quality for each production batch.
[0052] It can be understood that in some embodiments, the first protrusion 410 can also have additional functions, such as increasing heat dissipation performance, improving mechanical strength, etc. For example, a small texture or hole structure can be added to the surface of the first protrusion 410, which does not affect the height consistency, but can play a role in auxiliary heat dissipation, or by adjusting the protrusion shape (such as round, square) to change the contact area, thereby affecting the heat conduction efficiency.
[0053] In some embodiments, the height H1 of the first protrusion 410 satisfies 0 μm < H1 ≤ 100 μm, for example, H1 is 1 μm, 10 μm, 30 μm, 60 μm, 90 μm, 100 μm; the length L1 of the first protrusion 410 satisfies 10 mm ≤ L1 ≤ 400 mm, for example, L1 is 10 mm, 20 mm, 50 mm, 100, 150 mm, 200 mm, 250 mm, 400 mm; the width D1 of the first protrusion 410 satisfies 10 mm ≤ D1 ≤ 200 mm, for example, D1 is 10 mm, 50 mm, 100 mm, 150 mm, 200 mm. The above data aims to find the best balance point, so that the cathode sheet can provide sufficient mechanical support and maintain appropriate flexibility, so as to facilitate the manufacturing and use of the battery cell.
[0054] Specifically, the height H1 of the first protrusion 410 is not more than 100 pm, which ensures that it does not cause unnecessary pressure on the adjacent layers, while avoiding assembly difficulties due to excessive height. The length L1 and width D1 are set in consideration of the actual application scenarios of the cathode sheet, i.e. sufficient length to adapt to different specifications of battery units, and moderate width to ensure good mechanical strength without sacrificing flexibility. Within this range, the first protrusion 410 can effectively enhance the connection stability between the active material layer and the substrate layer without affecting the overall structure. Such a size range ensures that the first protrusion 410 can effectively support the active material layer, and does not affect the flexibility and assembly convenience of the entire cathode sheet due to excessive volume.
[0055] In some embodiments, in addition to a simple rectangular cross-section, other geometric shapes of the first protrusion 410 can be configured, such as trapezoidal, semicircular, etc., to optimize mechanical performance or improve current conduction paths. In addition, reasonable planning of the spatial distribution pattern of multiple first protrusions 410, such as staggered arrangement, matrix arrangement, etc., can improve heat dissipation efficiency or reduce stress concentration phenomenon.
[0056] Referring to Figure 4 and Figure 5 , the first protrusion 410 extends along the length direction of the cathode sheet, and along the length direction of the cathode sheet, the end of the third protrusion 430 and the end of the long-film-surface active material layer 500 are flush. And along the length direction of the cathode sheet, the end of the first protrusion 410 and the end of the short-film-surface active material layer 600 are aligned to enhance the overall anti-tear capability of the bare cell cathode sheet and particularly the end-of-life empty aluminum foil or single-sided area, reduce abuse failure conditions such as dropping / rolling, and at the same time improve the flatness of the cell.
[0057] Of course, it can be understood that in some embodiments, only the end of the cathode sheet is provided with the first protrusion 410, and along the length direction of the cathode sheet, the end of the short-film-surface active material layer 600 is aligned with the end of the first protrusion 410; in some embodiments, the protrusion structure 400 includes multiple first protrusions 410 distributed along the length direction of the cathode sheet, and along the length direction of the cathode sheet, the end of the first protrusion 410 located at the end of the cathode sheet is aligned with the end of the short-film-surface active material layer 600. Such design can improve the flatness of the cell.
[0058] In some embodiments, the number of first protrusions 410 and the spacing therebetween can be adjusted according to actual application requirements. For example, more protrusions are added where higher strength is needed, and the number of protrusions is reduced or the spacing is increased where flexibility is more important.
[0059] Referring to Figures 1 to 3In some embodiments, the protrusion structure 400 further comprises a plurality of second protrusions 420 spacedly arranged, each of the plurality of second protrusions 420 being connected to the first protrusions 410 on a side facing away from the intermediate layer 100, and each of the plurality of second protrusions 420 and / or the gaps between the plurality of second protrusions 420 being adapted to be connected to the hot melt adhesive. The presence of the second protrusions 420 provides additional attachment points for the hot melt adhesive, forming a composite protrusion structure 400 composed of the first protrusions 410 and the second protrusions 420 to ensure that sufficient bonding area is provided when the hot melt adhesive is used. Specifically, when the hot melt adhesive is heated to a molten state, it will adhere to the second protrusions 420 and / or flow into the gaps between the second protrusions 420, and after re-solidification as the temperature decreases, a firm connection is formed. This process not only strengthens the physical connection between the layers, but also improves the durability and resistance of the entire cathode sheet, i.e., improves the tear resistance of the end-of-life aluminum foil or single-sided area, and reduces misuse failure such as dropping / rolling.
[0060] It can be understood that, in some embodiments, the gaps for accommodating the hot melt adhesive between the second protrusions 420 arranged at intervals can be simulated by forming grooves on the first protrusions 410, so as to achieve the purpose of strengthening the bonding effect. It can be understood that, in some embodiments, the cathode sheet comprises a plurality of first protrusions 410 arranged at intervals, and the gaps between the plurality of first protrusions 410 can serve as gaps for accommodating the hot melt adhesive.
[0061] In some embodiments, the height H2 of the first protrusions 410 and / or the second protrusions 420 and / or the third protrusions 430 satisfies 0 < H2 < 100 μm, for example, H2 is 1 μm, 20 μm, 50 μm, 80 μm, or 100 μm; the length L2 of the first protrusions 410 and / or the second protrusions 420 and / or the third protrusions 430 satisfies a length range of 10 mm < L2 < 400 mm, for example, L2 is 10 mm, 100 mm, 200 mm, 300 mm, or 400 mm; the width D2 of the first protrusions 410 and / or the second protrusions 420 and / or the third protrusions 430 satisfies 10 mm < D2 < 200 mm, for example, D2 is 10 mm, 50 mm, 100 mm, 150 mm, or 200 mm; and the spacing S of each of the first protrusions and / or the second protrusions and / or the third protrusions satisfies 0 < S < 90 mm, for example, S is 1 mm, 20 mm, 40 mm, 60 mm, or 90 mm. Such a size range and distribution pattern ensures that the third protrusions 430 can effectively enhance the bonding strength between the cathode sheet and other components, while not affecting the flexibility and assembly convenience of the entire structure.
[0062] Specifically, when the height H2 of the third protrusions 430 is controlled within a reasonable range, the problem of excessive height leading to assembly difficulties or excessive pressure on other layers can be avoided. The length L2 and the width D2 are set not only to provide sufficient contact area to enhance adhesion, but also to maintain a certain degree of flexibility so that the cathode sheet can not be broken when bent or folded. The spacing S between the third protrusions 430 is designed to allow the hot melt adhesive to fully fill the gap between the individual third protrusions 430 and form a solid connection after re-solidification with temperature changes, which not only strengthens the physical connection between the layers, but also improves the durability and vibration resistance of the entire cathode sheet. The second protrusions 420 have similar beneficial effects.
[0063] In some embodiments, the intermediate layer 100 comprises copper foil and its alloys or other metals, alloys, the thickness H3 of the intermediate layer 100 satisfies 1 pm≤H3≤6 pm, for example, H3 is 1 pm, 2 pm, 3 pm, 4 pm, 5 pm, 6 pm; the length L3 satisfies 50 mm≤L3≤2450 mm, for example, L3 is 50 mm, 1000 mm, 1500 mm, 2000 mm, 2450 mm; the width D3 satisfies 10 mm≤D3≤200 mm, for example, D3 is 10 mm, 50 mm, 150 mm, 200 mm. In some embodiments, the outer surface layer 300 comprises aluminum foil and its alloys or other metals, alloys, the thickness H4 of the outer surface layer 300 satisfies 0.5 pm≤H4≤3 pm, for example, H4 is 0.5 pm, 1, 1.5 pm, 2 pm, 2.5 pm, 3 pm. In some embodiments, the inner surface layer 200 comprises aluminum foil and its alloys or other metals, alloys, the thickness H5 of the inner surface layer 200 satisfies 0.5 pm≤H5≤3 pm, for example, H4 is 0.5 pm, 1, 1.5 pm, 2 pm, 2.5 pm, 3 pm.
[0064] The intermediate layer 100 uses copper foil as the main material, which is an ideal choice of substrate due to its excellent electrical conductivity and relatively low cost. The outer surface layer 300 and the inner surface layer 200 use aluminum foil, not only because aluminum has good electrical conductivity, but also because it is relatively light and easy to process. The selection of these materials and the setting of the size parameters together constitute a high-efficiency and stable cathode sheet structure. Through the optimized design of the materials and sizes of the intermediate layer 100, the outer surface layer 300 and the inner surface layer 200, the best balance of the cathode sheet in terms of electrical conductivity, mechanical stability and processing convenience is achieved. Especially on the basis of maintaining good electrical conductivity, the overall performance of the cathode sheet is significantly improved, the production cost is reduced, and the safety and reliability of the battery are enhanced.
[0065] In some embodiments, other metals or alloys with good electrical conductivity, such as nickel or silver-coated copper, are used to improve performance in certain special application scenarios. For the outer layer 300 and the inner layer 200, if higher corrosion resistance or lower resistivity is required, aluminum foil coated with an oxidation-resistant coating or other functional coating can be selected.
[0066] In some embodiments, the outer layer 300 and the inner layer 200 are subjected to appropriate surface treatment, such as roughening treatment, chemical conversion film treatment, etc., which can further improve the bonding force between them and the active material layer or other components, and enhance the stability of the overall structure. In addition, a nanoscale coating can also be introduced to improve the electrical contact properties between the interfaces.
[0067] Referring to Figures 1 to 5 Embodiments of the second aspect of the present application propose an electric core, which includes the cathode sheet of any of the preceding embodiments. The electric core further includes an anode sheet and a separator, and the separator is sandwiched between the cathode sheet and the anode sheet. In the electric core, the distance between the cathode sheet and the anode sheet is very close, but they cannot be in direct contact, so the separator is needed to ensure that they are both separated enough to avoid short circuiting, and allow charged particles such as lithium ions to pass through smoothly. When the battery is charging and discharging, lithium ions migrate from one electrode to another, passing through the separator to form a current loop. Figure 5 Due to the special designed protruding structure 400 of the cathode sheet, not only the mechanical strength of the cathode sheet itself is enhanced, but also the bonding force between the active material layer and the substrate layer is improved, so that the entire electric core is more stable and reliable during the cycle process. Moreover, due to the addition of the protruding structure 400 of the present application, the electric core can enhance the anti-tear ability of the overall bare electric core cathode sheet and especially the end aluminum foil or single-sided area, reduce the abuse failure conditions such as dropping / rolling, and improve the flatness of the electric core. The principle has been described above and will not be repeated here.
[0068] Referring to Figure 2 and Figure 3In some embodiments, the battery cell includes a tailing tape 700. In the thickness and length direction of the cathode sheet, the long film active material layer 500 end and the third protrusion 430 intersection exists to cover the tailing tape 700, and the cathode short film active material tail end 600 and the first protrusion 410 intersection exists to cover the tailing tape 700. Along the length direction of the cathode sheet, the tailing tape 700 covers the long film active material layer 500 tail end sheet length direction 1-4 mm, for example 1 mm, 2 mm, 3 mm, 4 mm, and the tailing tape 700 covers the third protrusion 430 size of 2-30 mm, for example 2 mm, 10 mm, 20 mm, 30 mm; and / or, along the length direction of the cathode sheet, the tailing tape 700 covers the short film active material layer 600 tail end sheet length direction 1-4 mm, for example 1 mm, 2 mm, 3 mm, 4 mm, and the tailing tape 700 covers the first protrusion 410 size of 2-30 mm, for example 2 mm, 10 mm, 20 mm, 30 mm. As shown in the design, the tailing tape 700 on the tail of the long film active material layer 500 is the thickest, and the first protrusion 410 avoids the thickest area. Figure 3 In some embodiments, the tailing tape 700 on the tail of the long film active material layer 500 is the thickest, and the first protrusion 410 avoids the thickest area.
[0069] In some embodiments, the battery cell is wound by a new type of step-like composite aluminum foil coated cathode sheet, a separator film, and an anode sheet. The battery cell body includes a flat section and a circular arc section. The two ends of the flat section are respectively provided with a circular arc section. The cathode sheet long film active material layer tail end exceeds the short film active material layer tail end by at least two flat sections. The active material layer tail end has high adhesive paper at least on the short film surface. The adhesive paper covers the active material layer by 1-4 mm, and covers the aluminum foil by 2-30 mm. The battery cell is tailed by the cathode aluminum foil or the single-sided area. The tailing adhesive is hot melt adhesive or high adhesive paper. The tailing adhesive covers the tailing aluminum foil or the single-sided area by 1-5 mm. The battery cell can have head and tail winding adhesives. The battery cell needs to be pasted with hot melt adhesive. The number of hot melt adhesives is at least 1 pcs. The hot melt adhesive area can be on the tailing surface or non-tailing surface of the battery cell. The head and tail winding adhesive paper or hot melt adhesive are conventional materials that meet industry standards. For reference Figure 5 The cathode aluminum foil is provided with a step-shaped appearance from the tail end of the short film and / or long film active material layer. The protrusion mode is as shown in Figure 1 , Figure 2 , Figure 3 , Figure 4 The protrusion structure 400 is at least one. The first protrusion 410 corresponds to the single-sided area aluminum foil of the short film tail end. The second protrusion 420 corresponds to the hot melt adhesive area. The third protrusion 430 is the protruding aluminum foil of the long film tail end section. At least one of the first protrusion 410, the second protrusion 420, and the third protrusion 430 exists. When the second protrusion 420 exists, the hot melt adhesive needs to be pasted on the second protrusion 420 and / or multiple 420 protrusion intervals.
[0070] In some embodiments, the application adheres a layer of Permacel P-94 double-sided tape on a 1 mm thick aluminum foil, adheres the composite current collector obtained in the embodiments on the double-sided tape, covers a layer of ethylene acrylic acid copolymer film (Dupont Nurcel0903, 50 μm thick) on the composite current collector, and then hot-presses at 1.3 x 105 N / m2, 120°C for 10 s, cools to room temperature, and cuts into 150 mm x 15 mm strips. Finally, the ethylene acrylic acid copolymer film of the sample strip is fixed to the upper clamp of the tensile testing machine, and the rest is fixed to the lower clamp. After fixing, the two are peeled at an angle of 180° at a speed of 100 mm / min, and the peeling strength is tested: the peeling strength of the aluminum layer of the cathode end aluminum foil is F≥3 N / 15 mm.
[0071] In some embodiments, the cathode composite aluminum foil is placed on a sample stage, and the sheet resistance of the sample is tested using a four-probe sheet resistance meter, and the sheet resistance is ≤8 Ω.
[0072] In some embodiments, the cathode end aluminum foil meets one or more of the following properties: puncture strength ≥ 100 gf, longitudinal tensile strength ≥ 22 kgf / mm2, transverse tensile strength ≥ 22 kgf / mm2, longitudinal elongation ≥ 2%, longitudinal elongation ≥ 2%; dyne value ≥ 30 Dyne / cm
[0073] The wound electrode core obtained in the above manner is placed in a conventional aluminum plastic film (aluminum plastic film thickness 75 μm-115 μm, conventional material meeting industry standards), and the top seal, liquid injection, formation, second seal, and shaping processes are performed according to conventional process parameters in the industry to obtain the example battery. The drop and roller tests are arranged, and the test operation method is in accordance with the relevant certification safety regulations, and the test results meet the requirements. For example, at room temperature, the battery is fully charged at a constant current and constant voltage of 0.2C or more, and the cutoff rate is 0.02C or 0.05C; the battery is dropped freely from a height of 1.5 m onto a concrete floor, with each direction of X, Y, and Z being dropped once in the positive and negative directions, for a total of 6 times; the example battery does not catch fire, does not explode, and does not smoke, and can meet the certification test.
[0074] Further, as a preferred embodiment, specifically, with reference to Figure 2 The substrate layer of the application contains first protrusions 410 and third protrusions 430, which connect the short film surface of the cathode sheet in the length direction of the cathode sheet and connect the long film surface of the cathode sheet in the thickness direction of the cathode sheet. The two protrusions are flush with the active material layer surface in the thickness direction of the cathode sheet. The end of the first protrusion 410 and the third protrusion 430 are aligned.
[0075] With reference to Figure 3 In some embodiments, further, in order to improve the flatness of the electrode core, the first protrusions 410 are designed to avoid the thickest area.
[0076] In summary, the battery cell of the present application can enhance the anti-tear ability of the overall bare cell cathode sheet, especially the end empty aluminum foil or single-sided area, reduce the abuse failure conditions such as drop / roller, and improve the flatness of the battery cell.
[0077] With reference to Figures 1 to 5 The third aspect of the present application provides a battery, which comprises the battery cell of any one of the preceding embodiments. The battery of the present application can enhance the anti-tear ability of the overall bare cell cathode sheet, especially the end empty aluminum foil or single-sided area, reduce the abuse failure conditions such as drop / roller, and improve the flatness of the battery cell.
[0078] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like made by using the content of the present application specification and drawings within the utility model concept of the present application are included in the patent protection scope of the present application.
Claims
1. A cathode sheet, characterized by, The cathode sheet comprises a substrate layer and an active material layer, the substrate layer comprises an intermediate layer, an outer surface layer, an inner surface layer, and a protruding structure, the intermediate layer is sandwiched between the outer surface layer and the inner surface layer, the protruding structure is arranged on the intermediate layer, the active material layer is connected to at least one side of the outer surface layer away from the intermediate layer and / or the inner surface layer away from the intermediate layer. The protruding structure is connected to one side of the intermediate layer facing the outer surface layer, and the outer surface layer wraps the protruding structure, and / or the protruding structure is connected to one side of the intermediate layer facing the inner surface layer, and the inner surface layer wraps the protruding structure.
2. The cathode sheet according to claim 1, characterized by The protruding structure comprises a first protrusion and a third protrusion, the active material layer comprises a long-film-face active material layer and a short-film-face active material layer, the long-film-face active material layer is connected to the inner surface layer, the short-film-face active material layer is connected to the outer surface layer, the length of the long-film-face active material layer is longer than the length of the short-film-face active material layer along the length direction of the cathode sheet, and the end of the first protrusion is flush with the end of the short-film-face active material layer, and the end of the third protrusion is flush with the end of the long-film-face active material layer along the length direction of the cathode sheet.
3. The cathode sheet according to claim 2, characterized by The short-film-face active material layer and the first protrusion are distributed along the length direction of the cathode sheet, the long-film-face active material layer and the third protrusion are distributed along the length direction of the cathode sheet, the height of the first protrusion and the short-film-face active material layer is consistent along the thickness direction of the cathode sheet, and the height of the third protrusion and the long-film-face active material layer is consistent along the thickness direction of the cathode sheet.
4. The cathode sheet according to claim 3, characterized by The height H1 of the first protrusion and the third protrusion satisfies 0 μm < H1 ≤ 100 μm, the length L1 satisfies 10 mm ≤ L1 ≤ 400 mm, and the width D1 satisfies 10 mm ≤ D1 ≤ 200 mm.
5. The cathode sheet according to claim 2, characterized by The first protrusion extends along the length direction of the cathode sheet, and the end of the first protrusion is flush with the end of the long-film-face active material layer along the length direction of the cathode sheet; and / or, The protruding structure comprises a plurality of first protrusions distributed along the length direction of the cathode sheet, the end of the first protrusion located at the end of the cathode sheet is flush with the end of the short-film-face active material layer along the length direction of the cathode sheet, and the recess between the plurality of first protrusions is suitable for connecting hot melt adhesive.
6. The cathode sheet according to claim 2, characterized by The first protrusion extends along the length direction of the cathode sheet, and the end of the first protrusion is flush with the end of the short-film-face active material layer along the length direction of the cathode sheet; and / or, the protruding structure comprises a plurality of second protrusions distributed along the length direction of the cathode sheet, the plurality of second protrusions are connected to one side of the first protrusion away from the intermediate layer and arranged above the first protrusion in the thickness direction, the plurality of second protrusions and / or the recess between the second protrusions are suitable for connecting hot melt adhesive, and / or the distance between the end of the second protrusion and the end of the first protrusion along the length direction of the cathode sheet is 20 mm-100 mm.
7. The cathode sheet according to any one of claims 5 or 6, characterized in that, The height H2 of the first protrusion and / or the second protrusion and / or the third protrusion satisfies 0 μm < H2 ≤ 100 μm, the length L2 satisfies the length range 10 mm ≤ L2 ≤ 400 mm, and the width D2 satisfies 10 mm ≤ D2 ≤ 200 mm; The interval S of each of the first protrusion and / or the second protrusion and / or the third protrusion satisfies 0 mm ≤ S ≤ 90 mm.
8. The cathode sheet according to claim 1, characterized by The intermediate layer comprises copper foil and its alloy or other metal, alloy, the thickness H3 of the intermediate layer satisfies 1 μm ≤ H3 ≤ 6 μm, the length L3 satisfies 50 mm ≤ L3 ≤ 2450 mm, and the width D3 satisfies 10 mm ≤ D3 ≤ 200 mm; The outer surface layer comprises aluminum foil and its alloy or other metal, alloy, the thickness H4 of the outer surface layer satisfies 0.5 μm ≤ H4 ≤ 3 μm; The inner surface layer comprises aluminum foil and its alloy or other metal, alloy, the thickness H5 of the inner surface layer satisfies 0.5 μm ≤ H4 ≤ 3 μm.
9. The cathode sheet of claim 1, wherein The end of the long film active material layer and the third protrusion are covered with a finishing tape along the thickness direction of the cathode sheet, the finishing end of the short film active material layer and the first protrusion are covered with the finishing tape, the finishing tape covers the finishing end of the long film active material layer by 1 mm-4 mm and covers the first protrusion by 2 mm-30 mm along the length direction of the cathode sheet; and / or, the finishing tape covers the finishing end of the short film active material layer by 1 mm-4 mm and covers the first protrusion by 2 mm-30 mm along the length direction of the cathode sheet.
10. An electric cell characterized by The electric core comprises the cathode sheet of any one of claims 1-9, and further comprises an anode sheet and a separator, the separator is clamped between the cathode sheet and the anode sheet.
11. A battery, characterized by The electric core comprises the electric core of claim 10. The electric core comprises the electric core of claim 10.